Nanoparticle ink composition, light-emitting device, and method of manufacturing the light-emitting device

ABSTRACT

A nanoparticle ink composition includes: a solvent; and one or more inorganic nanoparticles substantially dispersed in the solvent, wherein the inorganic nanoparticles include one or more quantum dots or a metal oxide having a diameter of about 20 nm or less, and the nanoparticle ink composition has an Ohnesorge number of about 0.1 to about 0.2.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean Patent Application No. 10-2020-0186765, filed on Dec. 29, 2020, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND Field

Embodiments of the invention relate generally to a nanoparticle ink composition, and more particularly, to a light-emitting device, and a method of manufacturing the light-emitting device.

Discussion of the Background

Light-emitting devices convert electrical energy into light energy. Examples of such light-emitting devices include organic light-emitting devices in which a light-emitting material is an organic material, and quantum dot light-emitting devices in which the light-emitting material is a quantum dot.

A light-emitting device may have a structure in which a first electrode, a hole transport region, an emission layer, an electron transport region, and a second electrode are sequentially formed. Holes provided from the first electrode may move toward the emission layer through the hole transport region, and electrons provided from the second electrode may move toward the emission layer through the electron transport region. The holes and the electrons recombine in the emission layer to produce excitons. These excitons transition from an excited state to a ground state to thereby generate light.

The above information disclosed in this Background section is only for understanding of the background of the inventive concepts, and, therefore, it may contain information that does not constitute prior art.

SUMMARY

Compositions made, light-emitting devices constructed, and/or methods according to illustrative implementations of the invention are capable of providing one or more embodiments of a nanoparticle ink composition, a light-emitting device, and a method of manufacturing the light-emitting device.

Additional features of the inventive concepts will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the inventive concepts.

According to one aspect of the invention, a nanoparticle ink composition includes: a solvent; and one or more inorganic nanoparticles substantially dispersed in the solvent, wherein the inorganic nanoparticles include one or more quantum dots or a metal oxide having a diameter of about 20 nm or less, and the nanoparticle ink composition has an Ohnesorge number of about 0.1 to about 0.2.

A light-emitting device may include: a first electrode; a second electrode facing the first electrode; and an interlayer between the first electrode and the second electrode, wherein the interlayer includes an emission layer, and at least one of layers included in the interlayer is made from the nanoparticle ink composition as described above.

A method of manufacturing a light-emitting device, the light-emitting device include: a first electrode; a second electrode facing the first electrode; and an interlayer between the first electrode and the second electrode, wherein the interlayer includes an emission layer, a hole-transporting region between the first electrode and the emission layer, and an electron-transporting region between the emission layer and the second electrode; and the method includes the steps of:

(A) forming the hole-transporting region on the first electrode,

(B) forming the emission layer on the hole-transporting region, and

(C) forming the electron-transporting region on the emission layer,

wherein at least one of the steps (A) to (C) includes using a solution including the nanoparticle ink composition as described above.

It is to be understood that both the foregoing general description and the following detailed description are illustrative and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate illustrative embodiments of the invention, and together with the description serve to explain the inventive concepts.

FIG. 1 shows a schematic cross-sectional view of an embodiment of a light-emitting device.

FIG. 2 is a schematic cross-sectional view of an embodiment of a light-emitting apparatus including a light-emitting device.

FIG. 3 is a schematic cross-sectional view of another embodiment of a light-emitting apparatus a light-emitting device.

FIG. 4 is a photographic result showing jetting test results of an ink composition of Example 1 of an embodiment.

FIG. 5 is a photographic result showing jetting test results of an ink composition of Example 2.

FIG. 6 is a photographic result jetting test results of an ink composition of Comparative Example 1.

FIG. 7 a photographic result jetting test results of an ink composition of Comparative Example 2.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of various embodiments or implementations of the invention. As used herein “embodiments” and “implementations” are interchangeable words that are non-limiting examples of devices or methods employing one or more of the inventive concepts disclosed herein. It is apparent, however, that various embodiments may be practiced without these specific details or with one or more equivalent arrangements. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring various embodiments. Further, various embodiments may be different, but do not have to be exclusive. For example, specific shapes, configurations, and characteristics of an embodiment may be used or implemented in another embodiment without departing from the inventive concepts.

Unless otherwise specified, the illustrated embodiments are to be understood as providing illustrative features of varying detail of some ways in which the inventive concepts may be implemented in practice. Therefore, unless otherwise specified, the features, components, modules, layers, films, panels, regions, and/or aspects, etc. (hereinafter individually or collectively referred to as “elements”), of the various embodiments may be otherwise combined, separated, interchanged, and/or rearranged without departing from the inventive concepts.

The use of cross-hatching and/or shading in the accompanying drawings is generally provided to clarify boundaries between adjacent elements. As such, neither the presence nor the absence of cross-hatching or shading conveys or indicates any preference or requirement for particular materials, material properties, dimensions, proportions, commonalities between illustrated elements, and/or any other characteristic, attribute, property, etc., of the elements, unless specified. Further, in the accompanying drawings, the size and relative sizes of elements may be exaggerated for clarity and/or descriptive purposes. When an embodiment may be implemented differently, a specific process order may be performed differently from the described order. For example, two consecutively described processes may be performed substantially at the same time or performed in an order opposite to the described order. Also, like reference numerals denote like elements.

When an element, such as a layer, is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it may be directly on, connected to, or coupled to the other element or layer or intervening elements or layers may be present. When, however, an element or layer is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers present. To this end, the term “connected” may refer to physical, electrical, and/or fluid connection, with or without intervening elements. Further, the D1-axis, the D2-axis, and the D3-axis are not limited to three axes of a rectangular coordinate system, such as the x, y, and z-axes, and may be interpreted in a broader sense. For example, the D1-axis, the D2-axis, and the D3-axis may be perpendicular to one another, or may represent different directions that are not perpendicular to one another. For the purposes of this disclosure, “at least one of X, Y, and Z” and “at least one selected from the group consisting of X, Y, and Z” may be construed as X only, Y only, Z only, or any combination of two or more of X, Y, and Z, such as, for instance, XYZ, XYY, YZ, and ZZ. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

Although the terms “first,” “second,” etc. may be used herein to describe various types of elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another element. Thus, a first element discussed below could be termed a second element without departing from the teachings of the disclosure.

Spatially relative terms, such as “beneath,” “below,” “under,” “lower,” “above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), and the like, may be used herein for descriptive purposes, and, thereby, to describe one elements relationship to another element(s) as illustrated in the drawings. Spatially relative terms are intended to encompass different orientations of an apparatus in use, operation, and/or manufacture in addition to the orientation depicted in the drawings. For example, if the apparatus in the drawings is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the term “below” can encompass both an orientation of above and below. Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90 degrees or at other orientations), and, as such, the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting. As used herein, the singular forms, “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Moreover, the terms “comprises,” “comprising,” “includes,” and/or “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The term “consist of” used herein refers to the existence of only the corresponding component while excluding the possibility that other components are added. For example, the wording “consist of A, B and C” refers to the existence of only A, B and C. It is also noted that, as used herein, the terms “substantially,” “about,” and other similar terms, are used as terms of approximation and not as terms of degree, and, as such, are utilized to account for inherent deviations in measured, calculated, and/or provided values that would be recognized by one of ordinary skill in the art.

Various embodiments are described herein with reference to sectional and/or exploded illustrations that are schematic illustrations of idealized embodiments and/or intermediate structures. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments disclosed herein should not necessarily be construed as limited to the particular illustrated shapes of regions, but are to include deviations in shapes that result from, for instance, manufacturing. In this manner, regions illustrated in the drawings may be schematic in nature and the shapes of these regions may not reflect actual shapes of regions of a device and, as such, are not necessarily intended to be limiting.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure is a part. Terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense, unless expressly so defined herein.

A nanoparticle ink composition according to one aspect includes a solvent, one or more inorganic nanoparticles dispersed in the solvent, wherein the inorganic nanoparticles are quantum dots or a metal oxide having a diameter of about 20 nanometer (nm) or less, and the nanoparticle ink composition has an Ohnesorge number of about 0.1 to about 0.2.

In this regard, the Ohnesorge number is a value consisting of the relationship between the surface tension and viscosity of an ink composition, and can be expressed by Equation 1 below.

$\begin{matrix} {{Oh} = {\eta/\left( {d\;{\rho\sigma}} \right)^{1/2}}} & {{Equation}\mspace{14mu} 1} \end{matrix}$

In Equation 1, Oh is the Ohnesorge number,

d is the diameter (microns (μm)) of an inkjet nozzle, and

η, ρ, and σ are the viscosity in centipoise (cP), density in gram per centimeter cubed (g/cm³) and surface tension in dyne per centimeter (dyne/cm) of the ink composition, respectively.

Conventionally, even when the weight percent (weight % or wt %) of particles in an ink composition, the boiling point of a solvent, the surface tension, the viscosity are all considered, jetting failure sometimes occur.

Within the Ohnesorge number condition of about 0.1 to about 0.2, the nanoparticle ink composition may be properly jetted. When the nanoparticle ink composition has an Ohnesorge number of less than about 0.1 or greater than about 0.2, the nanoparticle ink composition may not be jetted. In one or more embodiments, the surface tension of the nanoparticle ink composition may be from about 20 dyne/cm to about 50 dyne/cm.

In one or more embodiments, the viscosity of the nanoparticle ink composition at a temperature of 25° C. may be from about 1 cP (centipoise) to about 12 cP. In one or more embodiments, the density of the nanoparticle ink composition may be from about 0.8 g/cm³ to about 2.0 g/cm³. For example, the nanoparticle ink composition may consist of the solvent and the nanoparticles. In one or more embodiments, the solvent may be an alcohol-based solvent having two or more carbon atoms, an ether-based solvent, an aromatic solvent, or a combination thereof.

For example, the solvent may include an ether-based solvent or a mixture of ether-based solvents and other solvents. For example, the solvent may include a mixture of ether-based solvents and other solvents. In one or more embodiments, the solvent may have the boiling point of about 150° C. to about 350° C., about 170° C. to about 320° C., or about 200° C. to about 300° C. so that ink droplets are stably jetted to prevent ink dryness in a nozzle part of an inkjet print head.

For example, the solvent may include a cyclohexylbenzene (the boiling point of about 240° C.), 1,3-dipropoxybenzenne (the boiling point of about 251° C.), 4-methoxybenzaldehyde-dimethyl-acetal (the boiling point of about 253° C.), 4,4′-difluorodiphenylmethane (the boiling point of about 258° C.), diphenylether (the boiling point of about 259° C.), 1,2-dimethoxy-4-(1-propenyl)benzene (the boiling point of about 264° C.), 2-phenoxytoluene (the boiling point of about 265° C.), diphenylmethane (the boiling point of about 265° C.), 2-phenylpyridine (the boiling point of about 268° C.), dimethyl benzyl ether (the boiling point of about 270° C.), 3-phenoxytoluene (the boiling point of about 272° C.), 3-phenylpyridine (the boiling point of about 272° C.), 2-phenylanisole (the boiling point of about 274° C.), 2-phenoxytetrahydropuran (the boiling point of about 275° C.), 1-propyl-4-phenyl benzene (the boiling point of about 280° C.), 2-phenoxy-1,4-dimethyl benzene (the boiling point of about 280° C.), ethyl-2-naphthyl-ether (the boiling point of about 282° C.), dodecylbenzene (the boiling point of about 290° C.), 2,2,5-tri-methy diphenyl ether (the boiling point of about 290° C.), dibenzyl-ether (the boiling point of about 295° C.), 2,3,5-tri-methy diphenyl ether (the boiling point of about 295° C.), N-methyldiphenylamine (the boiling point of about 297° C.), 4-isopropylbiphenyl (the boiling point of about 298° C.), α,α-dichlorodiphenylmethane (the boiling point of about 305° C.), 4-(3-phenylpropyl)pyridine (the boiling point of about 322° C.), benzyl-benzoate (the boiling point of about 324° C.), 1,1-bis(3,4-dimethylphenyl)ethane (the boiling point of about 333° C.), diethyleneglycolbutylmethylether (DEGBME), diethyleneglycolmonomethylether (DEGME), diethyleneglycolethylmethylether (DEGEME), diethyleneglycoldibutylether (DEGDBE), propylene glycol methylether acetate (PGMEA), triethylene glycol monomethylether (TGME), diethyleneglycolmonobutyl ether (DGBE), or a combination thereof.

For example, the solvent may include a cyclohexylbenzene, a propylene glycol methyl ether acetate, a triethylene glycol monomethyl ether, a diethylene glycol monobutyl ether, or a combination thereof. In one or more embodiments, the amount of the inorganic nanoparticles may be about 10 wt % or less based on the total weight of the nanoparticle ink composition. In one or more embodiments, the amount of the inorganic nanoparticles may be less than about 10 wt % based on the total weight of the nanoparticle ink composition. For example, the amount of the inorganic nanoparticles may be from about 0.01 wt % to about 10 wt % based on the total weight of the nanoparticle ink composition. For example, the amount of the inorganic nanoparticles may be from about 0.05 wt % to about 10 wt % based on the total weight of the nanoparticle ink composition. For example, the amount of the inorganic nanoparticles may be from about 0.1 wt % to about 10 wt % based on the total weight of the nanoparticle ink composition.

A diameter of the quantum dot may be, for example, in a range of about 1 nm to about 10 nm. The quantum dot may be synthesized by a wet chemical process, a metal organic chemical vapor deposition process, a molecular beam epitaxy process, or any process similar thereto. According to the wet chemical process, a precursor material is mixed with an organic solvent to grow a quantum dot particle crystal. When the crystal grows, the organic solvent naturally acts as a dispersant coordinated on the surface of the quantum dot crystal and controls the growth of the crystal so that the growth of quantum dot particles can be controlled through a process which is more easily performed than vapor deposition methods, such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE), and which requires low costs.

The quantum dot may include a semiconductor compound of Groups II-VI, a semiconductor compound of Groups III-V, a semiconductor compound of Groups III-VI, a semiconductor compound of Groups I, III, and VI, a semiconductor compound of Groups IV-VI, an element or a compound of Group IV; or any combination thereof.

Examples of the semiconductor compound of Groups II-VI are a binary compound, such as CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, or MgS; a ternary compound, such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, or MgZnS; a quaternary compound, such as CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, or HgZnSTe; or any combination thereof.

Examples of the semiconductor compound of Groups III-V are a binary compound, such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or the like; a ternary compound, such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InAlP, InNAs, InNSb, InPAs, InPSb, or the like; a quaternary compound, such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or the like; or any combination thereof. The semiconductor compound of the Groups III-V may further include Group II elements. Examples of the semiconductor compound of Groups III-V further including Group II elements are InZnP, InGaZnP, InAlZnP, etc.

Examples of the semiconductor compound of Groups III-VI are a binary compound, such as GaS, GaSe, Ga₂Se₃, GaTe, InS, InSe, In₂S₃, In₂Se₃, or InTe; a ternary compound, such as InGaS₃, or InGaSe₃; and any combination thereof. Examples of the semiconductor compound of Groups I, III, and VI are a ternary compound, such as AgInS, AgInS₂, CuInS, CuInS₂, CuGaO₂, AgGaO₂, or AgAlO₂; or any combination thereof.

Examples of the semiconductor compound of Groups IV-VI are a binary compound, such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, or the like; a ternary compound, such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or the like; a quaternary compound, such as SnPbSSe, SnPbSeTe, SnPbSTe, or the like; or any combination thereof. The Group IV element or compound may include a single element compound, such as Si or Ge; a binary compound, such as SiC or SiGe; or any combination thereof.

Each element included in a multi-element compound such as the binary compound, ternary compound and quaternary compound, may exist in a particle with a uniform concentration or non-uniform concentration.

The quantum dot may have a single structure or a dual core-shell structure. In the case of the quantum dot having a single structure, the concentration of each element included in the corresponding quantum dot is uniform. In one or more embodiments, the material contained in the core and the material contained in the shell may be different from each other.

The shell of the quantum dot may act as a protective layer to prevent chemical degeneration of the core to maintain semiconductor characteristics and/or as a charging layer to impart electrophoretic characteristics to the quantum dot. The shell may be a single layer or a multi-layer. The interface between the core and the shell may have a concentration gradient that decreases toward the center of the element present in the shell.

Examples of the shell of the quantum dot may be an oxide of a metal, a metalloid, or a non-metal, a semiconductor compound, and any combination thereof. Examples of the oxide of a metal, a metalloid, or a non-metal are a binary compound, such as SiO₂, Al₂O₃, TiO₂, ZnO, MnO, Mn₂O₃, Mn₃O₄, CuO, FeO, Fe₂O₃, Fe₃O₄, CoO, Co₃O₄, or NiO; a ternary compound, such as MgAl₂O₄, CoFe₂O₄, NiFe₂O₄, or CoMn₂O₄; and any combination thereof. Examples of the semiconductor compound are, as described herein, semiconductor compounds of Groups II-VI; semiconductor compounds of Groups III-V; semiconductor compounds of Groups III-VI; semiconductor compounds of Groups I, III, and VI; semiconductor compounds of Groups IV-VI; and any combination thereof. In addition, the semiconductor compound may include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, or any combination thereof. In one or more embodiments, the quantum dot may include InP, GaP, InGaP, ZnSe, ZnS, ZnSeTe, or any combination thereof.

The full width at half maximum (FWHM) of an emission wavelength spectrum of the quantum dot may be about 45 nm or less, for example, about 40 nm or less, for example, about 30 nm or less, and within these ranges, color purity or color gamut may be increased. In addition, since the light emitted through the quantum dot is emitted in all directions, the wide viewing angle can be improved.

In addition, the quantum dot may be a generally spherical particle, a generally pyramidal particle, a generally multi-armed particle, a generally cubic nanoparticle, a generally nanotube-shaped particle, a generally nanowire-shaped particle, a generally nanofiber-shaped particle, or a generally nanoplate-shaped particle. Because the energy band gap can be adjusted by controlling the size of the quantum dot, light having various wavelength bands can be obtained from the quantum dot emission layer. Therefore, by using quantum dots of different sizes, a light-emitting device that emits light of various wavelengths may be implemented. In one or more embodiments, the size of the quantum dot may be selected to emit red, green and/or blue light. In addition, the size of the quantum dot may be configured to emit white light by combining light of various colors. For example, the diameter of the metal oxide may be less than about 20 nm. For example, the diameter of the metal oxide may be from about 0.1 nm to about 20 nm. For example, the diameter of the metal oxide may be from about 1 nm to about 20 nm.

In one or more embodiments, the metal oxide may be an alkali metal oxide, an alkaline earth metal-containing oxide, a rare earth metal-containing oxide, a transition metal oxide, or a combination thereof. In one or more embodiments, the metal oxide may be beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), iron (Fe), zinc (Zn), aluminum (Al), gallium (Ga), indium (In), silicon (Si), germanium (Ge), tin (Sn), copper (Cu), or any combination thereof. For example, the metal oxide may be ZnO, TiO₂, WO₃, MoO₃, or a combination thereof.

Light-Emitting Device

A light-emitting device according to another aspect includes: a first electrode; a second electrode opposite the first electrode; and an interlayer between the first electrode and the second electrode, wherein the interlayer includes an emission layer, and at least one of the interlayer may be formed using the nanoparticle ink composition.

Description of FIG. 1

FIG. 1 shows a schematic cross-sectional view of an embodiment of a light-emitting device.

The light-emitting device 10 includes a first electrode 110, an interlayer 130 and a second electrode 150, and the interlayer 130 includes an emission layer 133.

In one or more embodiments, the emission layer 133 may be formed using the nanoparticle ink composition. In this regard, the nanoparticle ink composition may include quantum dots. The quantum dot may be the same as described above. In one or more embodiments, the interlayer 130 may further include a hole-transporting region 131 between the first electrode 110 and the emission layer 133 and an electron-transporting region 135 between the emission layer 133 and the second electrode 150.

In one or more embodiments, the hole-transporting region 131 may include a hole injection layer (HIL), a hole-transporting layer (HTL), an emission auxiliary layer, an electron-blocking layer (EBL), or any combination thereof. The electron-transporting region 135 may include a buffer layer, a hole-blocking layer, an electron control layer, an electron transport layer, an electron injection layer, or any combination thereof. At least one layer of the layers included in the hole-transporting region 131 and the electron-transporting region 135 may be formed using the nanoparticle ink composition. In this regard, the nanoparticle ink composition may include a metal oxide. Description of the metal oxide may be the same as described above. Hereinafter, the structure of the light-emitting device 10 according to an embodiment and a method of manufacturing the light-emitting device 10 will be described in connection with FIG. 1.

First Electrode 110

In FIG. 1, a substrate may be additionally located under the first electrode 110 or above the second electrode 150. As the substrate, a glass substrate or a plastic substrate may be used. In one or more embodiments, the substrate may be a flexible substrate, and may include plastics with excellent heat resistance and durability, such as a polyimide, a polyethylene terephthalate (PET), a polycarbonate, a polyethylene naphthalate, a polyarylate (PAR), a polyetherimide, or any combination thereof.

The first electrode 110 may be formed by, for example, depositing or sputtering a material for forming the first electrode 110 on the substrate. When the first electrode 110 is an anode, a material for forming the first electrode 110 may be a high work function material that facilitates injection of holes.

The first electrode 110 may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. When the first electrode 110 is a transmissive electrode, a material for forming the first electrode 110 may include an indium tin oxide (ITO), an indium zinc oxide (IZO), a tin oxide (SnO₂), a zinc oxide (ZnO), or any combinations thereof. In one or more embodiments, when the first electrode 110 is a semi-transmissive electrode or a reflective electrode, magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), or any combinations thereof may be used as a material for forming a first electrode. The first electrode 110 may have a single layer consisting of a single-layered structure or a multilayer structure including a plurality of layers. For example, the first electrode 110 may have a three-layered structure of an ITO/Ag/ITO.

Interlayer 130

The interlayer 130 may be located on the first electrode 110. The interlayer 130 may include an emission layer 133. The interlayer 130 may further include a hole-transporting region 131 located between the first electrode 110 and the emission layer 133 and an electron-transporting region 135 located between the emission layer 133 and the second electrode 150.

The interlayer 130 may further include metal-containing compounds such as organometallic compounds, inorganic materials such as quantum dots, and the like, in addition to various organic materials. In one or more embodiments, the interlayer 130 may include, i) two or more emitting units sequentially stacked between the first electrode 110 and the second electrode 150 and ii) a charge generation layer located between the two emitting units. When the interlayer 130 includes the emitting unit and the charge generation layer as described above, the light-emitting device 10 may be a tandem light-emitting device.

Hole-Transporting Region 131 in Interlayer 130

The hole-transporting region 131 may have: i) a single-layered structure consisting of a single layer consisting of a single material, ii) a single-layered structure consisting of a single layer consisting of a plurality of different materials, or iii) a multi-layered structure including a plurality of layers including different materials.

The hole-transporting region 131 may include a hole injection layer (HIL), a hole-transporting layer (HTL), an emission auxiliary layer, an electron-blocking layer (EBL), or any combination thereof. For example, the hole-transporting region 131 may have a multi-layered structure including a hole injection layer/hole-transporting layer structure, a hole injection layer/hole-transporting layer/emission auxiliary layer structure, a hole injection layer/emission auxiliary layer structure, a hole-transporting layer/emission auxiliary layer structure, or a hole injection layer/hole-transporting layer/electron-blocking layer structure, wherein, in each structure, layers are stacked sequentially from the first electrode 110.

The hole-transporting region 131 may include a compound represented by Formula 201, a compound represented by Formula 202, or any combination thereof.

wherein, in Formulae 201 and 202,

L₂₀₁ to L₂₀₄ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a),

L₂₀₅ may be *—O—*′, *—S—*′, *—N(Q₂₀₁)-*′, a C₁-C₂₀ alkylene group unsubstituted or substituted with at least one R_(10a), a C₂-C₂₀ alkenylene group unsubstituted or substituted with at least one R_(10a), a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a), or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a),

xa1 to xa4 may each independently an integer from 0 to 5,

xa5 may be an integer from 1 to 10,

R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a),

R₂₀₁ and R₂₀₂ may optionally be linked to each other, via a single bond, a C₁-C₅ alkylene group unsubstituted or substituted with at least one R_(10a), or a C₂-C₅ alkenylene group unsubstituted or substituted with at least one R_(10a), to form a C₈-C₆₀ polycyclic group (for example, a carbazole group or the like) unsubstituted or substituted with at least one R_(10a) (for example, Compound HT16),

R₂₀₃ and R₂₀₄ may optionally be linked to each other, via a single bond, a C₁-C₅ alkylene group unsubstituted or substituted with at least one R_(10a), or a C₂-C₅ alkenylene group unsubstituted or substituted with at least one R_(10a), to form a C₈-C₆₀ polycyclic group unsubstituted or substituted with at least one R_(10a), and

na1 may be an integer from 1 to 4.

In one or more embodiments, each of Formulae 201 and 202 may include at least one of groups represented by Formulae CY201 to CY217.

R_(10b) and R_(10c) in Formulae CY201 to CY217 are the same as described in connection with R_(10a), ring CY₂₀₁ to ring CY₂₀₄ may each independently be a C₃-C₂₀ carbocyclic group or a C₁-C₂₀ heterocyclic group, and at least one hydrogen in Formulae CY201 to CY217 may be unsubstituted or substituted with R_(10a).

In one or more embodiments, ring CY₂₀₁ to ring CY₂₀₄ in Formulae CY201 to CY217 may each independently be a benzene group, a naphthalene group, a phenanthrene group, or an anthracene group. In one or more embodiments, each of Formulae 201 and 202 may include at least one of groups represented by Formulae CY201 to CY203. In one or more embodiments, Formula 201 may include at least one of groups represented by Formulae CY201 to CY203 and at least one of groups represented by Formulae CY204 to CY217.

In one or more embodiments, xa1 in Formula 201 is 1, R₂₀₁ is a group represented by one of Formulae CY201 to CY203, xa2 may be 0, and R₂₀₂ may be a group represented by one of Formulae CY204 to CY207. In one or more embodiments, each of Formulae 201 and 202 may not include a group represented by one of Formulae CY201 to CY203. In one or more embodiments, each of Formulae 201 and 202 may not include a group represented by one of Formulae CY201 to CY203, and may include at least one of groups represented by Formulae CY204 to CY217. In one or more embodiments, each of Formulae 201 and 202 may not include a group represented by one of Formulae CY201 to CY217.

In one or more embodiments, the hole-transporting region 131 may include one of Compounds HT1 to HT46, 4,4′,4″-tris[phenyl(m-tolyl)amino]triphenylamine (m-MTDATA), 1-N,1-N-bis[4-(diphenylamino)phenyl]-4-N,4-N-diphenylbenzene-1,4-diamine (TDATA), 4,4′,4″-tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA), bis(naphthalen-1-yl)-N,N′-bis(phenyl)benzidine (NPB or NPD), N4,N4′-di(naphthalen-2-yl)-N4,N4′-diphenyl-[1,1′-biphenyl]-4,4′-diamine (β-NPB), N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine (TPD), N,N′-bis(3-methylphenyl)-N,N′-diphenyl-9,9-spirobifluorene-2,7-diamine (spiro-TPD), N2,N7-di-1-naphthalenyl-N2,N7-diphenyl-9,9′-spirobi[9H-fluorene]-2,7-diamine (spiro-NPB), N,N′-di(1-naphthyl)-N,N′-diphenyl-2,2′-dimethyl-(1,1′-biphenyl)-4,4′-diamine (methylated NPB), 4,4′-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine] (TAPC), N,N,N′,N′-tetrakis(3-methylphenyl)-3,3′-dimethylbenzidine (HMTPD), 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), or any combination thereof:

The thickness of the hole-transporting region 131 may be in a range of about 50 Å to about 10,000 Å, for example, about 100 Å to about 4,000 Å. When the hole-transporting region 131 includes the hole injection layer, the hole-transporting layer, or any combination thereof, the thickness of the hole injection layer may be in a range of about 100 Å to about 9,000 Å, for example, about 100 Å to about 1,000 Å, and the thickness of the hole-transporting layer may be in a range of about 50 Å to about 2,000 Å, for example, about 100 Å to about 1,500 Å. When the thicknesses of the hole-transporting region 131, the hole injection layer and the hole-transporting layer are within these ranges, satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.

The emission auxiliary layer may increase light-emission efficiency by compensating for an optical resonance distance according to the wavelength of light emitted by an emission layer 133, and the electron blocking layer may block the flow of electrons from the electron-transporting region 135. The emission auxiliary layer and the electron blocking layer may include the materials as described above.

p-Dopant

The hole-transporting region 131 may further include, in addition to these materials, a charge-generation material for the improvement of conductive properties. The charge-generation material may be uniformly or non-uniformly dispersed in the hole-transporting region 131 (for example, in the form of a single layer consisting of a charge-generation material). The charge-generation material may be, for example, a p-dopant. In one or more embodiments, the lowest unoccupied molecular orbital (LUMO) energy level of the p-dopant may be about-3.5 eV or less.

In one or more embodiments, the p-dopant may include a quinone derivative, a cyano group-containing compound, a compound containing element EL1 and element EL2, or any combination thereof. Examples of the quinone derivative are tetracyanoquinodimethane (TCNQ), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), etc. Examples of the cyano group-containing compound are 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN), and a compound represented by Formula 221 below.

In Formula 221,

R₂₂₁ to R₂₂₃ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a), and

at least one of R₂₂₁ to R₂₂₃ may each independently be a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group, each substituted with a cyano group; —F; —Cl; —Br; —I; a C₁-C₂₀ alkyl group substituted with a cyano group, —F, —Cl, —Br, —I, or any combination thereof, or any combination thereof.

In the compound containing element EL1 and element EL2, element EL1 may be a metal, a metalloid, or a combination thereof, and element EL2 may be a non-metal, a metalloid, or a combination thereof. Examples of the metal are an alkali metal (for example, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), etc.); an alkaline earth metal (for example, beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), etc.); a transition metal (for example, titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), etc.); a post-transition metal (for example, zinc (Zn), indium (In), tin (Sn), etc.); and a lanthanide metal (for example, lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), etc.).

Examples of the metalloid are silicon (Si), antimony (Sb), and tellurium (Te). Examples of the non-metal are oxygen (O) and a halogen (for example, F, Cl, Br, I, etc.). In one or more embodiments, examples of the compound containing element EL1 and element EL2 are a metal oxide, a metal halide (for example, a metal fluoride, a metal chloride, a metal bromide, or a metal iodide), a metalloid halide (for example, a metalloid fluoride, a metalloid chloride, a metalloid bromide, or a metalloid iodide), a metal telluride, or any combination thereof.

Examples of the metal oxide are a tungsten oxide (for example, WO, W₂O₃, WO₂, WO₃, W₂O₅, etc.), a vanadium oxide (for example, VO, V₂O₃, VO₂, V₂O₅, etc.), a molybdenum oxide (MoO, Mo₂O₃, MoO₂, MoO₃, Mo₂O₅, etc.), and a rhenium oxide (for example, ReO3, etc.). Examples of the metal halide are an alkali metal halide, an alkaline earth metal halide, a transition metal halide, a post-transition metal halide, and a lanthanide metal halide. Examples of the alkali metal halide are LiF, NaF, KF, RbF, CsF, LiCl, NaCl, KCl, RbCl, CsCl, LiBr, NaBr, KBr, RbBr, CsBr, LiI, NaI, KI, RbI, and CsI.

Examples of the alkaline earth metal halide are BeF₂, MgF₂, CaF₂, SrF₂, BaF₂, BeCl₂, MgCl₂, CaCl₂, SrCl₂, BaCl₂, BeBr₂, MgBr₂, CaBr₂, SrBr₂, BaBr₂, BeI₂, MgI₂, CaI₂, SrI₂, and BaI₂. Examples of the transition metal halide are a titanium halide (for example, TiF₄, TiCl₄, TiBr₄, TiI₄, etc.), a zirconium halide (for example, ZrF₄, ZrCl₄, ZrBr₄, ZrI₄, etc.), a hafnium halide (for example, HfF₄, HfCl₄, HfBr₄, Hff₄, etc.), a vanadium halide (for example, VF₃, VCl₃, VBr₃, VI₃, etc.), a niobium halide (for example, NbF₃, NbCl₃, NbBr₃, NbI₃, etc.), a tantalum halide (for example, TaF₃, TaCl₃, TaBr₃, TaI₃, etc.), a chromium halide (for example, CrF₃, CrCl₃, CrBr₃, CrI₃, etc.), a molybdenum halide (for example, MoF₃, MoCl₃, MoBr₃, MoI₃, etc.), a tungsten halide (for example, WF₃, WCl₃, WBr₃, WI₃, etc.), a manganese halide (for example, MnF₂, MnCl₂, MnBr₂, MnI₂, etc.), a technetium halide (for example, TcF₂, TcCl₂, TcBr₂, TcI₂, etc.), a rhenium halide (for example, ReF₂, ReCl₂, ReBr₂, ReI₂, etc.), an iron halide (for example, FeF₂, FeCl₂, FeBr₂, FeI₂, etc.), a ruthenium halide (for example, RuF₂, RuCl₂, RuBr₂, RuI₂, etc.), an osmium halide (for example, OsF₂, OsCl₂, OsBr₂, OsI₂, etc.), a cobalt halide (for example, CoF₂, CoCl₂, CoBr₂, CoI₂, etc.), a rhodium halide (for example, RhF₂, RhCl₂, RhBr₂, RhI₂, etc.), an iridium halide (for example, IrF₂, IrCl₂, IrBr₂, IrI₂, etc.), a nickel halide (for example, NiF₂, NiCl₂, NiBr₂, NiI₂, etc.), a palladium halide (for example, PdF₂, PdCl₂, PdBr₂, PdI₂, etc.), a platinum halide (for example, PtF₂, PtCl₂, PtBr₂, PtI₂, etc.), a copper halide (for example, CuF, CuCl, CuBr, CuI, etc.), a silver halide (for example, AgF, AgCl, AgBr, AgI, etc.), and a gold halide (for example, AuF, AuCl, AuBr, AuI, etc.).

Examples of the post-transition metal halide are a zinc halide (for example, ZnF₂, ZnCl₂, ZnBr₂, ZnI₂, etc.), an indium halide (for example, InI₃, etc.), and a tin halide (for example, SnI₂, etc.). Examples of the lanthanide metal halide are YbF, YbF₂, YbF₃, SmF₃, YbCl, YbCl₂, YbCl₃, SmCl₃, YbBr, YbBr₂, YbBr₃, SmBr₃, YbI, YbI₂, YbI₃, and SmI₃. An example of the metalloid halide is an antimony halide (for example, SbCl₅, etc.).

Examples of the metal telluride are an alkali metal telluride (for example, Li₂Te, Na₂Te, K₂Te, Rb₂Te, Cs₂Te, etc.), an alkaline earth metal telluride (for example, BeTe, MgTe, CaTe, SrTe, BaTe, etc.), a transition metal telluride (for example, TiTe₂, ZrTe₂, HfTe₂, V₂Te₃, Nb₂Te₃, Ta₂Te₃, Cr₂Te₃, Mo₂Te₃, W₂Te₃, MnTe, TcTe, ReTe, FeTe, RuTe, OsTe, CoTe, RhTe, IrTe, NiTe, PdTe, PtTe, Cu₂Te, CuTe, Ag₂Te, AgTe, Au₂Te, etc.), a post-transition metal telluride (for example, ZnTe, etc.), and a lanthanide metal telluride (for example, LaTe, CeTe, PrTe, NdTe, PmTe, EuTe, GdTe, TbTe, DyTe, HoTe, ErTe, TmTe, YbTe, LuTe, etc.).

Emission Layer 133 in Interlayer 130

When the light-emitting device 10 is a full-color light-emitting device, the emission layer 133 may be patterned into a red emission layer, a green emission layer, and/or a blue emission layer, according to a subpixel. In one or more embodiments, the emission layer 133 may have a stacked structure of two or more layers of the red emission layer, the green emission layer, and the blue emission layer, in which the two or more layers contact each other or are separated from each other. In one or more embodiments, the emission layer may include two or more materials of a red light-emitting material, a green light-emitting material, and a blue light-emitting material, in which the two or more materials are mixed with each other in a single layer to emit white light.

The emission layer 133 may include a host and a dopant. The dopant may include a phosphorescent dopant, a fluorescent dopant, or any combination thereof. The amount of the dopant in the emission layer 133 may be from about 0.01 to about 15 parts by weight based on 100 parts by weight of the host. In one or more embodiments, the emission layer 133 may include a quantum dot. The emission layer 133 may include a delayed fluorescence material. The delayed fluorescence material may act as a host or a dopant in the emission layer 133.

The thickness of the emission layer 133 may be in a range of about 100 Å to about 1,000 Å, for example, about 200 Å to about 600 Å. When the thickness of the emission layer 133 is within these ranges, excellent light-emission characteristics may be obtained without a substantial increase in driving voltage.

Host

In one or more embodiments, the host may include a compound represented by Formula 301 below:

[Ar₃₀₁]_(xb11)-[(L₃₀₁)_(xb1)-R₃₀₁]_(xb21)  Formula 301

In Formula 301,

-   -   Ar₃₀₁ and L₃₀₁ may each independently be a C₃-C₆₀ carbocyclic         group unsubstituted or substituted with at least one R_(10a) or         a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at         least one R_(10a),     -   xb11 may be 1, 2, or 3,

xb1 may be an integer from 0 to 5,

R₃₀₁ may be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₆₀ alkyl group unsubstituted or substituted with at least one R_(10a), a C₂-C₆₀ alkenyl group unsubstituted or substituted with at least one R_(10a), a C₂-C₆₀ alkynyl group unsubstituted or substituted with at least one R_(10a), a C₁-C₆₀ alkoxy group unsubstituted or substituted with at least one R_(10a), a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a), a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a), —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂), —B(Q₃₀₁)(Q₃₀₂), —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), or —P(═O)(Q₃₀₁)(Q₃₀₂),

xb21 may be an integer from 1 to 5, and

Q₃₀₁ to Q₃₀₃ are the same as described in connection with Q₁.

For example, when xb11 in Formula 301 is 2 or more, two or more of Ar₃₀₁(s) may be linked to each other via a single bond.

In one or more embodiments, the host may include a compound represented by Formula 301-1, a compound represented by Formula 301-2, or any combination thereof:

In Formulae 301-1 to 301-2,

ring A₃₀₁ to ring A₃₀₄ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a),

X₃₀₁ may be O, S, N-[(L₃₀₄)_(xb4)-R₃₀₄], C(R₃₀₄)(R₃₀₅), or Si(R₃₀₄)(R₃₀₅),

xb22 and xb23 may each independently be 0, 1, or 2,

L₃₀₁, xb1, and R₃₀₁ are the same as described herein,

L₃₀₂ to L₃₀₄ may each independently be the same as described in connection with L₃₀₁,

xb2 to xb4 may each independently be the same as described in connection with xb1, and

R₃₀₂ to R₃₀₅ and R₃₁₁ to R₃₁₄ are the same as described in connection with R₃₀₁.

In one or more embodiments, the host may include an alkali earth metal complex, a post-transition metal complex, or a combination thereof. In one or more embodiments, the host may include a Be complex (for example, Compound H55), an Mg complex, a Zn complex, or a combination thereof.

In one or more embodiments, the host may include one of Compounds H1 to H124, 9,10-di(2-naphthyl)anthracene (ADN), 2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), 9,10-di-(2-naphthyl)-2-t-butyl-anthracene (TBADN), 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-di(carbazol-9-yl)benzene (mCP), 1,3,5-tri(carbazol-9-yl)benzene (TCP), 3,3-di(9H-carbazol-9-yl)biphenyl (mCBP), or any combination thereof:

Phosphorescent Dopant

In one or more embodiments, the phosphorescent dopant may include at least one transition metal as a central metal. The phosphorescent dopant may include a monodentate ligand, a bidentate ligand, a tridentate ligand, a tetradentate ligand, a pentadentate ligand, a hexadentate ligand, or any combination thereof. The phosphorescent dopant may be electrically neutral. For example, the phosphorescent dopant may include an organometallic compound represented by Formula 401:

In Formulae 401 and 402,

M may be transition metal (for example, iridium (Ir), platinum (Pt), palladium (Pd), osmium (Os), titanium (Ti), gold (Au)hafnium (Hf), europium (Eu), terbium (Tb), rhodium (Rh), rhenium (Re), or thulium (Tm)),

L₄₀₁ may be a ligand represented by Formula 402, and xc1 may be 1, 2, or 3, wherein when xc1 is two or more, two or more of L₄₀₁(s) may be identical to or different from each other,

L₄₀₂ may be an organic ligand, and xc2 may be 0, 1, 2, 3, or 4, and when xc2 is 2 or more, two or more of L₄₀₂(s) may be identical to or different from each other,

X₄₀₁ and X₄₀₂ may each independently be nitrogen or carbon,

ring A₄₀₁ and ring A₄₀₂ may each independently be a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group,

T₄₀₁ may be a single bond, *—O—*′, *—S—*′, *—C(═O)—*′, *—N(Q₄₁₁)-*′, *—C(Q₄₁₁)(Q₄₁₂)-*′, *—C(Q₄₁₁)═C(Q₄₁₂)-*′, *—C(Q₄₁₁)=*′, or *═C═*′,

X₄₀₃ and X₄₀₄ may each independently be a chemical bond (for example, a covalent bond or a coordination bond), O, S, N(Q₄₁₃), B(Q₄₁₃), P(Q₄₁₃), C(Q₄₁₃)(Q₄₁₄), or Si(Q₄₁₃)(Q₄₁₄),

Q₄₁₁ to Q₄₁₄ are the same as described in connection with Q₁,

R₄₀₁ and R₄₀₂ may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₂₀ alkyl group unsubstituted or substituted with at least one R_(10a), a C₁-C₂₀ alkoxy group unsubstituted or substituted with at least one R_(10a), a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a), a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a), —Si(Q₄₀₁)(Q₄₀₂)(Q₄₀₃), —N(Q₄₀₁)(Q₄₀₂), —B(Q₄₀₁)(Q₄₀₂), —C(═O)(Q₄₀₁), —S(═O)₂(Q₄₀₁), or —P(═O)(Q₄₀₁)(Q₄₀₂),

Q₄₀₁ to Q₄₀₃ are the same as described in connection with Q₁,

xc11 and xc12 may each independently be an integer from 0 to 10,

* and *′ in Formula 402 each indicate a binding site to M in Formula 401.

For example, in Formula 402, i) X₄₀₁ is nitrogen, and X₄₀₂ is carbon, or ii) each of X₄₀₁ and X₄₀₂ is nitrogen.

In one or more embodiments, when xc1 in Formula 402 is 2 or more, two ring A₄₀₁ in two or more of L₄₀₁(s) may be optionally linked to each other via T₄₀₂, which is a linking group, and two ring A₄₀₂ may optionally be linked to each other via T₄₀₃, which is a linking group (see Compounds PD1 to PD4 and PD7). The variables T₄₀₂ and T₄₀₃ are the same as described in connection with T₄₀₁.

The variable L₄₀₂ in Formula 401 may be an organic ligand. For example, L₄₀₂ may include a halogen group, a diketone group (for example, an acetylacetonate group), a carboxylic acid group (for example, a picolinate group), a —C(═O) group, an isonitrile group, a —CN group, a phosphorus group (for example, a phosphine group, a phosphite group, etc.), or any combination thereof.

The phosphorescent dopant may include, for example, one of compounds PD1 to PD25, or any combination thereof:

Fluorescent Dopant

The fluorescent dopant may include an amine group-containing compound, a styryl group-containing compound, or any combination thereof.

In one or more embodiments, the fluorescent dopant may include a compound represented by Formula 501:

wherein, in Formula 501,

Ar₅₀₁, L₅₀₁ to L₅₀₃, R₅₀₁, and R₅₀₂ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a),

xd1 to xd3 may each independently be 0, 1, 2, or 3,

xd4 may be 1, 2, 3, 4, 5, or 6.

In one or more embodiments, Ar₅₀₁ in Formula 501 may be a condensed cyclic group (for example, an anthracene group, a chrysene group, or a pyrene group) in which three or more monocyclic groups are condensed together.

In one or more embodiments, xd4 in Formula 501 may be 2.

In one or more embodiments, the fluorescent dopant may include: one of Compounds FD1 to FD36; DPVBi; DPAVBi; or any combination thereof:

Delayed Fluorescence Material

The emission layer 133 may include a delayed fluorescence material. As used herein, the delayed fluorescence material may be selected from compounds capable of emitting delayed fluorescence based on the delayed fluorescence emission mechanism.

The delayed fluorescence material included in the emission layer 133 may act as a host or a dopant depending on the type of other materials included in the emission layer 133.

In one or more embodiments, the difference between the triplet energy level (eV) of the delayed fluorescence material and the singlet energy level (eV) of the delayed fluorescence material may be greater than or equal to about 0 eV and less than or equal to about 0.5 eV. When the difference between the triplet energy level (eV) of the delayed fluorescence material and the singlet energy level (eV) of the delayed fluorescence material satisfies the above-described range, up-conversion from the triplet state to the singlet state of the delayed fluorescence materials may effectively occur, and thus, the emission efficiency of the light-emitting device 10 may be improved.

In one or more embodiments, the delayed fluorescence material may include i) a material including at least one electron donor (for example, a π electron-rich C₃-C₆₀ cyclic group, such as a carbazole group) and at least one electron acceptor (for example, a sulfoxide group, a cyano group, or a π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group), and ii) a material including a C₈-C₆₀ polycyclic group in which two or more cyclic groups are condensed while sharing boron (B).

In one or more embodiments, the delayed fluorescence material may include at least one of the following compounds DF1 to DF9:

Quantum Dot

In one or more embodiments, the emission layer 133 may include a quantum dot. The quantum dot refers to a crystal of a semiconductor compound, and may include any material capable of emitting light of various emission wavelengths according to the size of the crystal. The diameter of the quantum dot may be, for example, in a range of about 1 nm to about 10 nm. The quantum dot may be synthesized by a wet chemical process, a metal organic chemical vapor deposition process, a molecular beam epitaxy process, or any process similar thereto.

According to the wet chemical process, a precursor material is mixed with an organic solvent to grow a quantum dot particle crystal. When the crystal grows, the organic solvent naturally acts as a dispersant coordinated on the surface of the quantum dot crystal and controls the growth of the crystal so that the growth of quantum dot particles can be controlled through a process which is more easily performed than vapor deposition methods, such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE), and which requires low costs.

The quantum dot may include semiconductor compounds of Groups II-VI, semiconductor compounds of Groups III-V, semiconductor compounds of Groups III-VI, semiconductor compounds of Groups I, III, and VI, semiconductor compounds of Groups IV-VI, an element or a compound of Group IV; or any combination thereof.

Examples of the semiconductor compound of Groups II-VI are a binary compound, such as CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, or MgS; a ternary compound, such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, or MgZnS; a quaternary compound, such as CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, or HgZnSTe; or any combination thereof.

Examples of the semiconductor compound of Groups III-V are a binary compound, such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or the like; a ternary compound, such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InAlP, InNAs, InNSb, InPAs, InPSb, or the like; a quaternary compound, such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or the like; or any combination thereof. The semiconductor compound of the Groups III-V may further include Group II elements. Examples of the semiconductor compound of Groups III-V further including Group II elements are InZnP, InGaZnP, InAlZnP, etc.

Examples of the semiconductor compound of Groups III-VI are a binary compound, such as GaS, GaSe, Ga₂Se₃, GaTe, InS, InSe, In₂S₃, In₂Se₃, or InTe; a ternary compound, such as InGaS₃, or InGaSe₃; and any combination thereof. Examples of the semiconductor compound of Groups I, III, and VI are a ternary compound, such as AgInS, AgInS₂, CuInS, CuInS₂, CuGaO₂, AgGaO₂, or AgAlO₂; or any combination thereof. Examples of the semiconductor compound of Groups IV-VI are a binary compound, such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, or the like; a ternary compound, such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or the like; a quaternary compound, such as SnPbSSe, SnPbSeTe, SnPbSTe, or the like; or any combination thereof.

The Group IV element or compound may include a single element compound, such as Si or Ge; a binary compound, such as SiC or SiGe; or any combination thereof. Each element included in a multi-element compound such as the binary compound, ternary compound and quaternary compound, may exist in a particle with a uniform concentration or non-uniform concentration. The quantum dot may have a single structure or a dual core-shell structure. In the case of the quantum dot having a single structure, the concentration of each element included in the corresponding quantum dot is uniform. In one or more embodiments, the material contained in the core and the material contained in the shell may be different from each other.

The shell of the quantum dot may act as a protective layer to prevent chemical degeneration of the core to maintain semiconductor characteristics and/or as a charging layer to impart electrophoretic characteristics to the quantum dot. The shell may be a single layer or a multi-layer. The interface between the core and the shell may have a concentration gradient that decreases toward the center of the element present in the shell.

Examples of the shell of the quantum dot may be an oxide of a metal, a metalloid, or a non-metal, a semiconductor compound, and any combination thereof. Examples of the oxide of a metal, a metalloid, or a non-metal are a binary compound, such as SiO₂, Al₂O₃, TiO₂, ZnO, MnO, Mn₂O₃, Mn₃O₄, CuO, FeO, Fe₂O₃, Fe₃O₄, CoO, Co₃O₄, or NiO; a ternary compound, such as MgAl₂O₄, CoFe₂O₄, NiFe₂O₄, or CoMn₂O₄; and any combination thereof. Examples of the semiconductor compound are, as described herein, semiconductor compounds of Groups II-VI; semiconductor compounds of Groups III-V; semiconductor compounds of Groups III-VI; semiconductor compounds of Groups I, III, and VI; semiconductor compounds of Groups IV-VI; and any combination thereof. In addition, the semiconductor compound may include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, or any combination thereof.

The full width at half maximum (FWHM) of an emission wavelength spectrum of the quantum dot may be about 45 nm or less, for example, about 40 nm or less, for example, about 30 nm or less, and within these ranges, color purity or color gamut may be increased. In addition, since the light emitted through the quantum dot is emitted in all directions, the wide viewing angle can be improved. In addition, the quantum dot may be a generally spherical particle, a generally pyramidal particle, and other particle shapes, and the energy band gap can be adjusted, as described above

Electron-Transporting Region 135 in Interlayer 130

The electron-transporting region 135 may have: i) a single-layered structure consisting of a single layer consisting of a single material, ii) a single-layered structure consisting of a single layer consisting of a plurality of different materials, or iii) a multi-layered structure including a plurality of layers including different materials.

The electron-transporting region 135 may include a buffer layer, a hole-blocking layer, an electron control layer, an electron transport layer, an electron injection layer, or any combination thereof. In one or more embodiments, the electron-transporting region 135 may have an electron transport layer/electron injection layer structure, a hole-blocking layer/electron transport layer/electron injection layer structure, an electron control layer/electron transport layer/electron injection layer structure, or a buffer layer/electron transport layer/electron injection layer structure, wherein, for each structure, constituting layers are sequentially stacked from the emission layer 133.

In one or more embodiments, the electron-transporting region 135 (for example, the buffer layer, the hole-blocking layer, the electron control layer, or the electron-transporting layer (ETL) in the electron-transporting region 135) may include a metal-free compound including at least one a electron-deficient nitrogen-containing C₁-C₆₀ cyclic group.

In one or more embodiments, the electron-transporting region 135 may include a compound represented by Formula 601 below:

[Ar₆₀₁]_(xe11)-[(L₆₀₁)_(xe1)-R₆₀₁]_(xe21)  Formula 601

wherein, in Formula 601,

Ar₆₀₁ and L₆₀₁ may each independently be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a),

xe11 may be 1, 2, or 3,

xe1 may be 0, 1, 2, 3, 4, or 5,

R₆₀₁ may be a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a), a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a), —Si(Q₆₀₁)(Q₆₀₂)(Q₆₀₃), —C(═O)(Q₆₀₁), —S(═O)₂(Q₆₀₁), or —P(═O)(Q₆₀₁)(Q₆₀₂),

Q₆₀₁ to Q₆₀₃ are the same as described in connection with Q₁,

xe21 may be 1, 2, 3, 4, or 5,

at least one of Ar₆₀₁, L₆₀₁, and R₆₀₁ may each independently be a π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group unsubstituted or substituted with at least one R_(10a).

For example, when xe11 in Formula 601 is 2 or more, two or more of Ar₆₀₁(s) may be linked via a single bond. In one or more embodiments, Ar₆₀₁ in Formula 601 may be a substituted or unsubstituted anthracene group. In one or more embodiments, the electron-transporting region 135 may include a compound represented by Formula 601-1:

In Formula 601-1,

X₆₁₄ may be N or C(R₆₁₄), X₆₁₅ may be N or C(R₆₁₅), X₆₁₆ may be N or C(R₆₁₆), at least one of X₆₁₄ to X₆₁₆ may be N,

L₆₁₁ to L₆₁₃ are the same as described in connection with L₆₀₁,

xe611 to xe613 are the same as described in connection with xe1,

R₆₁₁ to R₆₁₃ are the same as described in connection with R₆₀₁,

R₆₁₄ to R₆₁₆ may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a C₃-C₆₀ carbocyclic group unsubstituted or substituted with at least one R_(10a), or a C₁-C₆₀ heterocyclic group unsubstituted or substituted with at least one R_(10a).

For example, xe1 and xe611 to xe613 in Formulae 601 and 601-1 may each independently be 0, 1, or 2.

The electron-transporting region 135 may include one of Compounds ET1 to ET45, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), tris-(8-hydroxyquinoline)aluminum (AlQ₃), bis(2-methyl-8-quinolinolato-N1,O8)-(1,1′-biphenyl-4-olato)aluminum (BAlq), 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole (TAZ), 4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), diphenyl(4-(triphenylsilyl)phenyl)-phosphine oxide (TSPO1), or any combination thereof:

The thickness of the electron-transporting region 135 may be from about 160 Å to about 5,000 Å, for example, about 100 Å to about 4,000 Å. When the electron-transporting region 135 includes a buffer layer, a hole-blocking layer, an electron control layer, an electron transport layer, or any combination thereof, the thickness of the buffer layer, the hole blocking layer, or the electron control layer may each independently be from about 20 Å to about 1000 Å, for example, about 30 Å to about 300 Å, and the thickness of the electron transport layer may be from about 100 Å to about 1000 Å, for example, about 150 Å to about 500 Å. When the thicknesses of the buffer layer, hole-blocking layer, electron control layer, electron-transporting layer and/or electron-transporting layer are within these ranges, satisfactory electron transporting characteristics may be obtained without a substantial increase in driving voltage.

The electron-transporting region 135 (for example, the electron transport layer in the electron-transporting region 135) may further include, in addition to the materials described above, a metal-containing material. The metal-containing material may include an alkali metal complex, alkaline earth metal complex, or any combination thereof. The metal ion of an alkali metal complex may be a Li ion, a Na ion, a K ion, a Rb ion, or a Cs ion, and the metal ion of alkaline earth metal complex may be a Be ion, a Mg ion, a Ca ion, a Sr ion, or a Ba ion. A ligand coordinated with the metal ion of the alkali metal complex or the alkaline earth-metal complex may include a hydroxyquinoline, a hydroxyisoquinoline, a hydroxybenzoquinoline, a hydroxyacridine, a hydroxyphenanthridine, a hydroxyphenyloxazole, a hydroxyphenylthiazole, a hydroxyphenyloxadiazole, a hydroxyphenylthiadiazole, a hydroxyphenylpyridine, a hydroxyphenylbenzimidazole, a hydroxyphenylbenzothiazole, a bipyridine, a phenanthroline, a cyclopentadiene, or any combination thereof.

For example, the metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (lithium quinolate, LiQ) or ET-D2:

The electron-transporting region 135 may include an electron injection layer that facilitates the injection of electrons from the second electrode 150. The electron injection layer may directly contact the second electrode 150.

The electron injection layer may have: i) a single-layered structure consisting of a single layer consisting of a single material, ii) a single-layered structure consisting of a single layer consisting of a plurality of different materials, or iii) a multi-layered structure including a plurality of layers including different materials. The electron injection layer may include an alkali metal, alkaline earth metal, a rare earth metal, an alkali metal-containing compound, alkaline earth metal-containing compound, a rare earth metal-containing compound, an alkali metal complex, alkaline earth metal complex, a rare earth metal complex, or any combination thereof. The alkali metal may include Li, Na, K, Rb, Cs, or any combination thereof. The alkaline earth metal may include Mg, Ca, Sr, Ba, or any combination thereof. The rare earth metal may include Sc, Y, Ce, Tb, Yb, Gd, or any combination thereof.

The alkali metal-containing compound, the alkaline earth metal-containing compound, and the rare earth metal-containing compound may be oxides, halides (for example, fluorides, chlorides, bromides, or iodides), or tellurides of the alkali metal, the alkaline earth metal, and the rare earth metal, or any combination thereof. The alkali metal-containing compound may include alkali metal oxides, such as Li₂O, Cs₂O, or K₂O, alkali metal halides, such as LiF, NaF, CsF, KF, LiI, NaI, CsI, or KI, or any combination thereof.

The alkaline earth metal-containing compound may include an alkaline earth metal compound, such as BaO, SrO, CaO, Ba_(x)Sr_(1-x)O (x is a real number satisfying the condition of 0<x<1), Ba_(x)Ca_(1-x)O (x is a real number satisfying the condition of 0<x<1), or the like. The rare earth metal-containing compound may include YbF₃, ScF₃, Sc₂O₃, Y₂O₃, Ce₂O₃, GdF₃, TbF₃, YbI₃, ScI₃, TbI₃, or any combination thereof. In one or more embodiments, the rare earth metal-containing compound may include a lanthanide metal telluride. Examples of the lanthanide metal telluride are LaTe, CeTe, PrTe, NdTe, PmTe, SmTe, EuTe, GdTe, TbTe, DyTe, HoTe, ErTe, TmTe, YbTe, LuTe, La₂Te₃, Ce₂Te₃, Pr₂Te₃, Nd₂Te₃, Pm₂Te₃, Sm₂Te₃, Eu₂Te₃, Gd₂Te₃, Tb₂Te₃, Dy₂Te₃, Ho₂Te₃, Er₂Te₃, Tm₂Te₃, Yb₂Te₃, and Lu₂Te₃.

The alkali metal complex, the alkaline earth-metal complex, and the rare earth metal complex may include i) one of ions of the alkali metal, the alkaline earth metal, and the rare earth metal and ii), as a ligand bonded to the metal ion, for example, a hydroxyquinoline, a hydroxyisoquinoline, a hydroxybenzoquinoline, a hydroxyacridine, a hydroxyphenanthridine, a hydroxyphenyloxazole, a hydroxyphenylthiazole, a hydroxyphenyloxadiazole, a hydroxyphenylthiadiazole, a hydroxyphenylpyridine, a hydroxyphenyl benzimidazole, a hydroxyphenylbenzothiazole, a bipyridine, a phenanthroline, a cyclopentadiene, or any combination thereof.

The electron injection layer may consist of an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal-containing compound, an alkaline earth metal-containing compound, a rare earth metal-containing compound, an alkali metal complex, an alkaline earth metal complex, a rare earth metal complex, or any combination thereof, as described above. In one or more embodiments, the electron injection layer may further include an organic material (for example, a compound represented by Formula 601).

In one or more embodiments, the electron injection layer may consist of i) an alkali metal-containing compound (for example, an alkali metal halide), ii) a) an alkali metal-containing compound (for example, an alkali metal halide); and b) an alkali metal, an alkaline earth metal, a rare earth metal, or any combination thereof. In one or more embodiments, the electron injection layer may be a KI:Yb co-deposited layer, an RbI:Yb co-deposited layer, or the like. When the electron injection layer further includes an organic material, an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal-containing compound, an alkaline earth metal-containing compound, a rare earth metal-containing compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combination thereof may be homogeneously or non-homogeneously dispersed in a matrix including the organic material.

The thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, and, for example, about 3 Å to about 90 Å. When the thickness of the electron injection layer is within the range described above, the electron injection layer may have satisfactory electron injection characteristics without a substantial increase in driving voltage.

Second Electrode 150

The second electrode 150 may be located on the interlayer 130 having such a structure. The second electrode 150 may be a cathode, which is an electron injection electrode, and as the material for the second electrode 150, a metal, an alloy, an electrically conductive compound, or any combination thereof, each having a low work function, may be used.

In one or more embodiments, the second electrode 150 may include lithium (Li), silver (Ag), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), ytterbium (Yb), silver-ytterbium (Ag—Yb), an ITO, an IZO, or a combination thereof. The second electrode 150 may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode. The second electrode 150 may have a single-layered structure or a multi-layered structure including two or more layers.

Capping Layer

A first capping layer may be located outside the first electrode 110, and/or a second capping layer may be located outside the second electrode 150. In detail, the light-emitting device 10 may have a structure in which the first capping layer, the first electrode 110, the interlayer 130, and the second electrode 150 are sequentially stacked in this stated order, a structure in which the first electrode 110, the interlayer 130, the second electrode 150, and the second capping layer are sequentially stacked in this stated order, or a structure in which the first capping layer, the first electrode 110, the interlayer 130, the second electrode 150, and the second capping layer are sequentially stacked in this stated order.

Light generated in the emission layer 133 of the interlayer 130 of the light-emitting device 10 may be extracted toward the outside through the first electrode 110, which is a semi-transmissive electrode or a transmissive electrode, and the first capping layer or light generated in the emission layer 133 of the interlayer 130 of the light-emitting device 10 may be extracted toward the outside through the second electrode 150, which is a semi-transmissive electrode or a transmissive electrode, and the second capping layer.

The first capping layer and the second capping layer may increase external emission efficiency according to the principle of constructive interference. Accordingly, the light extraction efficiency of the light-emitting device 10 is increased, so that the emission efficiency of the light-emitting device 10 may be improved. Each of the first capping layer and second capping layer may include a material having a refractive index (at 589 nm) of about 1.6 or more.

The first capping layer and the second capping layer may each independently be an organic capping layer including an organic material, an inorganic capping layer including an inorganic material, or a composite capping layer including an organic material and an inorganic material. At least one selected from the first capping layer and the second capping layer may each independently include carbocyclic compounds, heterocyclic compounds, amine group-containing compounds, porphyrin derivatives, phthalocyanine derivatives, naphthalocyanine derivatives, alkali metal complexes, alkaline earth metal complexes, or any combination thereof. The carbocyclic compound, the heterocyclic compound, and the amine group-containing compound may be optionally substituted with a substituent containing O, N, S, Se, Si, F, Cl, Br, I, or any combination thereof. In one or more embodiments, at least one of the first capping layer and the second capping layer may each independently include an amine group-containing compound.

In one or more embodiments, at least one of the first capping layer and the second capping layer may each independently include a compound represented by Formula 201, a compound represented by Formula 202, or any combination thereof. In one or more embodiments, at least one of the first capping layer and the second capping layer may each independently include one of Compounds HT28 to HT33, one of Compounds CP1 to CP6, β-NPB, or any combination thereof:

Electronic Apparatus

The light-emitting device may be included in various electronic apparatuses. In one or more embodiments, the electronic apparatus including the light-emitting device may be a light-emitting apparatus, an authentication apparatus, or the like.

The electronic apparatus (for example, light-emitting apparatus) may further include, in addition to the light-emitting device, i) a color filter, ii) a color conversion layer, or iii) a color filter and a color conversion layer. The color filter and/or the color conversion layer may be located in at least one traveling direction of light emitted from the light-emitting device. In one or more embodiments, the light emitted from the light-emitting device may be blue light or white light. The light-emitting device may be the same as described above. In one or more embodiments, the color conversion layer may include quantum dots. The quantum dot may be, for example, a quantum dot as described herein.

The electronic apparatus may include a first substrate. The first substrate may include a plurality of subpixel areas, the color filter may include a plurality of color filter areas respectively corresponding to the subpixel areas, and the color conversion layer may include a plurality of color conversion areas respectively corresponding to the subpixel areas. A pixel-defining film may be located among the subpixel areas to define each of the subpixel areas.

The color filter may further include a plurality of color filter areas and light-shielding patterns located among the color filter areas, and the color conversion layer may include a plurality of color conversion areas and light-shielding patterns located among the color conversion areas.

The color filter areas (or the color conversion areas) may include a first area emitting first color light, a second area emitting second color light, and/or a third area emitting third color light, and the first color light, the second color light, and/or the third color light may have different maximum emission wavelengths from one another. In one or more embodiments, the first color light may be red light, the second color light may be green light, and the third color light may be blue light. In one or more embodiments, the color filter areas (or the color conversion areas) may include quantum dots. In detail, the first area may include a red quantum dot, the second area may include a green quantum dot, and the third area may not include a quantum dot. The quantum dot is the same as described herein. The first area, the second area, and/or the third area may each include a scatter.

In one or more embodiments, the light-emitting device may emit first light, the first area may absorb the first light to emit first first-color light, the second area may absorb the first light to emit second first-color light, and the third area may absorb the first light to emit third first-color light. In this regard, the first first-color light, the second first-color light, and the third first-color light may have different maximum emission wavelengths. In detail, the first light may be blue light, the first first-color light may be red light, the second first-color light may be green light, and the third first-color light may be blue light.

The electronic apparatus may further include a thin-film transistor in addition to the light-emitting device as described above. The thin-film transistor may include a source electrode, a drain electrode, and an activation layer, wherein any one of the source electrode and the drain electrode may be electrically connected to any one of the first electrode and the second electrode of the light-emitting device. The thin-film transistor may further include a gate electrode, a gate insulating film, etc. The activation layer may include a crystalline silicon, an amorphous silicon, an organic semiconductor, an oxide semiconductor, or the like.

The electronic apparatus may further include a sealing portion for sealing the light-emitting device. The sealing portion and/or the color conversion layer may be placed between the color filter and the light-emitting device. The sealing portion allows light from the light-emitting device to be extracted to the outside, while simultaneously preventing ambient air and moisture from penetrating into the light-emitting device. The sealing portion may be a sealing substrate including a transparent glass substrate or a plastic substrate. The sealing portion may be a thin-film encapsulation layer including at least one layer of an organic layer and/or an inorganic layer. When the sealing portion is a thin film encapsulation layer, the electronic apparatus may be flexible.

Various functional layers may be additionally located on the sealing portion, in addition to the color filter and/or the color conversion layer, according to the use of the electronic apparatus. The functional layers may include a touch screen layer, a polarizing layer, and the like. The touch screen layer may be a pressure-sensitive touch screen layer, a capacitive touch screen layer, or an infrared touch screen layer. The authentication apparatus may be, for example, a biometric authentication apparatus that authenticates an individual by using biometric information of a living body (for example, fingertips, pupils, etc.). The authentication apparatus may further include, in addition to the light-emitting device, a biometric information collector.

The electronic apparatus may take the form of or be applied to various displays, light sources, lighting, personal computers (for example, a mobile personal computer), mobile phones, digital cameras, electronic organizers, electronic dictionaries, electronic game machines, medical instruments (for example, electronic thermometers, sphygmomanometers, blood glucose meters, pulse measurement devices, pulse wave measurement devices, electrocardiogram displays, ultrasonic diagnostic devices, or endoscope displays), fish finders, various measuring instruments, meters (for example, meters for a vehicle, an aircraft, and a vessel), projectors, and the like.

Description of FIGS. 2 and 3

FIG. 2 is a schematic cross-sectional view of an embodiment of a light-emitting apparatus including a light-emitting device.

The light-emitting apparatus 180 of FIG. 2 includes a substrate 100, a thin-film transistor (TFT) 200, a light-emitting device 10, and an encapsulation portion 300 that seals the light-emitting device 10.

The substrate 100 may be a flexible substrate, a glass substrate, or a metal substrate. A buffer layer 210 may be formed on the substrate 100. The buffer layer 210 may prevent penetration of impurities through the substrate 100 and may provide a substantially flat surface on the substrate 100.

The TFT 200 may be located on the buffer layer 210. The TFT 200 may include an activation layer 220, a gate electrode 240, a source electrode 260, and a drain electrode 270. The activation layer 220 may include an inorganic semiconductor such as a silicon or a polysilicon, an organic semiconductor, or an oxide semiconductor, and may include a source region, a drain region and a channel region.

A gate insulating film 230 for insulating the activation layer 220 from the gate electrode 240 may be located on the activation layer 220, and the gate electrode 240 may be located on the gate insulating film 230. An interlayer insulating film 250 is located on the gate electrode 240. The interlayer insulating film 250 may be placed between the gate electrode 240 and the source electrode 260 to insulate the gate electrode 240 from the source electrode 260 and between the gate electrode 240 and the drain electrode 270 to insulate the gate electrode 240 from the drain electrode 270. The source electrode 260 and the drain electrode 270 may be located on the interlayer insulating film 250. The interlayer insulating film 250 and the gate insulating film 230 may be formed to expose the source region and the drain region of the activation layer 220, and the source electrode 260 and the drain electrode 270 may be in contact with the exposed portions of the source region and the drain region of the activation layer 220.

The TFT 200 is electrically connected to a light-emitting device 10 to drive the light-emitting device 10, and is covered by a passivation layer 280. The passivation layer 280 may include an inorganic insulating film, an organic insulating film, or a combination thereof. A light-emitting device 10 is provided on the passivation layer 280. The light-emitting device 10 may include a first electrode 110, an interlayer 130, and a second electrode 150.

The first electrode 110 may be formed on the passivation layer 280. The passivation layer 280 does not completely cover the drain electrode 270 and exposes a portion of the drain electrode 270, and the first electrode 110 is connected to the exposed portion of the drain electrode 270. A pixel defining layer 290 containing an insulating material may be located on the first electrode 110. The pixel defining layer 290 exposes a region of the first electrode 110, and an interlayer 130 may be formed in the exposed region of the first electrode 110. The pixel defining layer 290 may be a polyimide or a polyacrylic organic film. At least some layers of the interlayer 130 may extend beyond the upper portion of the pixel defining layer 290 to be located in the form of a common layer.

The second electrode 150 may be located on the interlayer 130, and a capping layer 170 may be additionally formed on the second electrode 150. The capping layer 170 may be formed to cover the second electrode 150. The encapsulation portion 300 may be located on the capping layer 170. The encapsulation portion 300 may be located on a light-emitting device 10 to protect the light-emitting device 10 from moisture or oxygen. The encapsulation portion 300 may include: an inorganic film including a silicon nitride (SiN_(x)), a silicon oxide (SiO_(x)), an indium tin oxide, an indium zinc oxide, or any combination thereof, an organic film including a polyethylene terephthalate, a polyethylene naphthalate, a polycarbonate, a polyimide, a polyethylene sulfonate, a polyoxymethylene, a polyarylate, a hexamethyldisiloxane, an acrylic resin (for example, a polymethyl methacrylate, a polyacrylic acid, or the like), an epoxy-based resin (for example, an aliphatic glycidyl ether (AGE), or the like), or a combination thereof, or a combination of the inorganic film and the organic film.

FIG. 3 is a schematic cross-sectional view of another embodiment of a light-emitting apparatus a light-emitting device.

The light-emitting apparatus 190 of FIG. 3 is substantially the same as the light-emitting apparatus 180 of FIG. 2, except that a light-shielding pattern 500 and a functional region 400 are additionally located on the encapsulation portion 300. The functional region 400 may be a combination of i) a color filter area, ii) a color conversion area, or iii) a combination of the color filter area and the color conversion area. In one or more embodiments, the light-emitting device 10 included in the light-emitting apparatus 190 of FIG. 3 may be a tandem light-emitting device.

Method of Manufacturing Light-Emitting Device

A method of manufacturing a light-emitting device according to an aspect includes (A) forming a hole-transporting region on a first electrode; (B) forming an emission layer on the hole-transporting region; and (C) forming an electron-transporting region on the emission layer, wherein at least one of (A) to (C) includes a solution process step using the nanoparticle ink composition.

In the method of manufacturing a light-emitting device according to an embodiment, (A) includes a solution process using the nanoparticle ink composition, and the nanoparticle ink composition may include the metal oxide. In the method of manufacturing a light-emitting device according to an embodiment, (B) includes a solution process using the nanoparticle ink composition, and the nanoparticle ink composition may include the quantum dot.

In the method of manufacturing a light-emitting device according to an embodiment, (C) includes a solution process using the nanoparticle ink composition, and the nanoparticle ink composition may include the metal oxide. In one or more embodiments, the solution process step may be performed using an inkjet printing method. As the inkjet printer used in the inkjet printing method, a known inkjet printer may be used.

Because at least one layer of a hole-transporting region, an emission layer, and an electron-transporting region included in the light-emitting device is formed by using the nanoparticle ink composition, large-area light-emitting devices having high quality can be manufactured efficiently.

Each of the layers of the hole-transporting region, the emission layer, and the electron-transporting region, other than the layer formed using a solution process using the nanoparticle ink composition, may be formed in a certain area by various methods, such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) deposition, ink-jet printing, laser-printing, and laser-induced thermal imaging.

When layers constituting the hole-transporting region 131, the emission layer 133, and layers constituting the electron-transporting region 135 are formed by a vacuum deposition, the deposition may be performed at a deposition temperature of about 100° C. to about 500° C., a vacuum degree of about 10⁻⁸ torr to about 10⁻³ torr, and a deposition speed of about 0.01 Å/sec to about 100 Å/sec, depending on a material to be included in a layer to be formed and the structure of a layer to be formed.

Definition of Terms

The term “Group I” as used herein may include Group IB elements on the IUPAC periodic table, and Group I elements may include, for example, copper (Cu), silver (Ag), gold (Au), and the like.

The term “Group II” as used herein may include a Group IIA element and a Group IIB element on the IUPAC periodic table, and the Group II element includes, for example, magnesium (Mg), calcium (Ca), zinc (Zn), cadmium (Cd), and mercury (Hg).

The term “Group III” as used herein may include a Group IIIA element and a Group IIIB element on the IUPAC periodic table, and the Group III element may include, for example, aluminum (Al), gallium (Ga), indium (In), and thallium (Tl).

The term “Group IV” as used herein may include a Group IVA element and a Group IVB element on the IUPAC periodic table, and the Group II element includes, for example, carbon (C), silicon (Si), germanium (Ge), tin (Sn), and lead (Pb).

The term “Group V” as used herein may include a Group VA element and a Group VB element on the IUPAC periodic table, and the Group V element may include, for example, nitrogen (N), phosphorus (P), arsenic (As), and antimony (Sb).

The term “Group VI” as used herein may include a Group VIA element and a Group VIB element on the IUPAC periodic table, and the Group VI element may include, for example, sulfur (S), selenium (Se), and tellurium (Te).

The term “interlayer” as used herein refers to a single layer and/or all layers between a first electrode and a second electrode of a light-emitting device. A material included in the “middle layer” is not limited to an organic material.

As used herein, a quantum dot refers to a crystal of a semiconductor compound, and may include any material capable of emitting light of various emission wavelengths according to the size of the crystal.

As used herein, the term “atom” may mean an element or its corresponding radical bonded to one or more other atoms.

The terms “hydrogen” and “deuterium” refer to their respective atoms and corresponding radicals, and the terms “—F, —Cl, —Br, and —I” are radicals of, respectively, fluorine, chlorine, bromine, and iodine.

As used herein, a substituent for a monovalent group, e.g., alkyl, may also be, independently, a substituent for a corresponding divalent group, e.g., alkylene.

The term “C₃-C₆₀ carbocyclic group” as used herein refers to a cyclic group consisting of carbon only and having three to sixty carbon atoms, and the term “C₁-C₆₀ heterocyclic group” as used herein refers to a cyclic group that has one to sixty carbon atoms and further has, in addition to carbon, a heteroatom. The C₃-C₆₀ carbocyclic group and the C₁-C₆₀ heterocyclic group may each be a monocyclic group consisting of one ring or a polycyclic group in which two or more rings are fused with each other. For example, the number of ring-forming atoms of the C₁-C₆₀ heterocyclic group may be from 3 to 61.

The “cyclic group” as used herein may include the C₃-C₆₀ carbocyclic group, and the C₁-C₆₀ heterocyclic group.

The term “π electron-rich C₃-C₆₀ cyclic group” as used herein refers to a cyclic group that has three to sixty carbon atoms and does not include *—N═*′ as a ring-forming moiety, and the term “π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group” as used herein refers to a heterocyclic group that has one to sixty carbon atoms and includes *—N═*′ as a ring-forming moiety.

For example, the C₃-C₆₀ carbocyclic group may be i) a group T1 or ii) a fused cyclic group in which two or more groups T1 are fused with each other, for example, a cyclopentadiene group, an adamantane group, a norbornane group, a benzene group, a pentalene group, a naphthalene group, an azulene group, an indacene group, an acenaphthylene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a perylene group, a pentaphene group, a heptalene group, a naphthacene group, a picene group, a hexacene group, a pentacene group, a rubicene group, a coronene group, an ovalene group, an indene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, an indenophenanthrene group, or an indenoanthracene group.

The C₁-C₆₀ heterocyclic group may be i) a group T2, ii) a fused cyclic group in which two or more groups T2 are fused with each other, or iii) a fused cyclic group in which at least one group T2 and at least one group T1 are fused with each other, for example, a pyrrole group, a thiophene group, a furan group, an indole group, a benzoindole group, a naphthoindole group, an isoindole group, a benzoisoindole group, a naphthoisoindole group, a benzosilole group, a benzothiophene group, a benzofuran group, a carbazole group, a dibenzosilole group, a dibenzothiophene group, a dibenzofuran group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, a benzosilolocarbazole group, a benzoindolocarbazole group, a benzocarbazole group, a benzonaphthofuran group, a benzonaphthothiophene group, a benzonaphthosilole group, a benzofurodibenzofuran group, a benzofurodibenzothiophene group, a benzothienodibenzothiophene group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzoisoxazole group, a benzothiazole group, a benzoisothiazole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a benzoisoquinoline group, a quinoxaline group, a benzoquinoxaline group, a quinazoline group, a benzoquinazoline group, a phenanthroline group, a cinnoline group, a phthalazine group, a naphthyridine group, an imidazopyridine group, an imidazopyrimidine group, an imidazotriazine group, an imidazopyrazine group, an imidazopyridazine group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, an azadibenzothiophene group, an azadibenzofuran group, etc.

The π electron-rich C₃-C₆₀ cyclic group may be i) a group T1, ii) a fused cyclic group in which two or more groups T1 are fused with each other, iii) a group T3, iv) a fused cyclic group in which two or more groups T3 are fused with each other, or v) a fused cyclic group in which at least one group T3 and at least one group T1 are fused with each other, for example, the C₃-C₆₀ carbocyclic group, a pyrrole group, a thiophene group, a furan group, an indole group, a benzoindole group, a naphthoindole group, an isoindole group, a benzoisoindole group, a naphthoisoindole group, a benzosilole group, a benzothiophene group, a benzofuran group, a carbazole group, a dibenzosilole group, a dibenzothiophene group, a dibenzofuran group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, a benzosilolocarbazole group, a benzoindolocarbazole group, a benzocarbazole group, a benzonaphthofuran group, a benzonaphthothiophene group, a benzonaphthosilole group, a benzofurodibenzofuran group, a benzofurodibenzothiophene group, a benzothienodibenzothiophene group, etc.

The π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group may be i) a group T4, ii) a fused cyclic group in which two or more group T4 are fused with each other, iii) a fused cyclic group in which at least one group T4 and at least one group T1 are fused with each other, iv) a fused cyclic group in which at least one group T4 and at least one group T3 are fused with each other, or v) a fused cyclic group in which at least one group T4, at least one group T1, and at least one group T3 are fused with one another, for example, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzoisoxazole group, a benzothiazole group, a benzoisothiazole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a benzoisoquinoline group, a quinoxaline group, a benzoquinoxaline group, a quinazoline group, a benzoquinazoline group, a phenanthroline group, a cinnoline group, a phthalazine group, a naphthyridine group, an imidazopyridine group, an imidazopyrimidine group, an imidazotriazine group, an imidazopyrazine group, an imidazopyridazine group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, an azadibenzothiophene group, an azadibenzofuran group, etc.

The group T1 may be a cyclopropane group, a cyclobutane group, a cyclopentane group, a cyclohexane group, a cycloheptane group, a cyclooctane group, a cyclobutene group, a cyclopentene group, a cyclopentadiene group, a cyclohexene group, a cyclohexadiene group, a cycloheptene group, an adamantane group, a norbornane (or a bicyclo[2.2.1]heptane) group, a norbornene group, a bicyclo[1.1.1]pentane group, a bicyclo[2.1.1]hexane group, a bicyclo[2.2.2]octane group, or a benzene group,

the group T2 may be a furan group, a thiophene group, a 1H-pyrrole group, a silole group, a borole group, a 2H-pyrrole group, a 3H-pyrrole group, an imidazole group, a pyrazole group, a triazole group, a tetrazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, an azasilole group, an azaborole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, or a tetrazine group,

the group T3 may be a furan group, a thiophene group, a 1H-pyrrole group, a silole group, or a borole group, and

the group T4 may be a 2H-pyrrole group, a 3H-pyrrole group, an imidazole group, a pyrazole group, a triazole group, a tetrazole group, an oxazole group, an isoxazole group, an oxadiazole group, a thiazole group, an isothiazole group, a thiadiazole group, an azasilole group, an azaborole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, or a tetrazine group.

The term “the cyclic group, the C₃-C₆₀ carbocyclic group, the C₁-C₆₀ heterocyclic group, the π electron-rich C₃-C₆₀ cyclic group, or the π electron-deficient nitrogen-containing C₁-C₆₀ cyclic group” as used herein refer to a group fused to any cyclic group or a polyvalent group (for example, a divalent group, a trivalent group, a tetravalent group, etc.), depending on the structure of a formula in connection with which the terms are used. In one or more embodiments, “a benzene group” may be a benzo group, a phenyl group, a phenylene group, or the like, which may be easily understood by one of ordinary skill in the art according to the structure of a formula including the “benzene group.”

Examples of the monovalent C₃-C₆₀ carbocyclic group and the monovalent C₁-C₆₀ heterocyclic group are a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic fused polycyclic group, and a monovalent non-aromatic fused heteropolycyclic group, and examples of the divalent C₃-C₆₀ carbocyclic group and the monovalent C₁-C₆₀ heterocyclic group are a C₃-C₁₀ cycloalkylene group, a C₁-C₁₀ heterocycloalkylene group, a C₃-C₁₀ cycloalkenylene group, a C₁-C₁₀ heterocycloalkenylene group, a C₆-C₆₀ arylene group, a C₁-C₆₀ heteroarylene group, a divalent non-aromatic fused polycyclic group, and a substituted or unsubstituted divalent non-aromatic fused heteropolycyclic group.

The term “C₁-C₆₀ alkyl group” as used herein refers to a linear or branched aliphatic hydrocarbon monovalent group that has one to sixty carbon atoms, and examples thereof are a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, a neopentyl group, an isopentyl group, a sec-pentyl group, a 3-pentyl group, a sec-isopentyl group, an n-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptyl group, an n-octyl group, an isooctyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonyl group, an n-decyl group, an isodecyl group, a sec-decyl group, and a tert-decyl group. The term “C₁-C₆₀ alkylene group” as used herein refers to a divalent group having a structure corresponding to the C₁-C₆₀ alkyl group.

The term “C₂-C₆₀ alkenyl group” as used herein refers to a monovalent hydrocarbon group having at least one carbon-carbon double bond in the middle or at the terminus of the C₂-C₆₀ alkyl group, and examples thereof are an ethenyl group, a propenyl group, and a butenyl group. The term “C₂-C₆₀ alkenylene group” as used herein refers to a divalent group having a structure corresponding to the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein refers to a monovalent hydrocarbon group having at least one carbon-carbon triple bond in the middle or at the terminus of the C₂-C₆₀ alkyl group, and examples thereof include an ethynyl group and a propynyl group. The term “C₂-C₆₀ alkynylene group” as used herein refers to a divalent group having a structure corresponding to the C₂-C₆₀ alkynyl group.

The term “C₁-C₆₀ alkoxy group” as used herein refers to a monovalent group represented by —OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group), and examples thereof include a methoxy group, an ethoxy group, and an isopropyloxy group.

The term “C₃-C₁₀ cycloalkyl group” as used herein refers to a monovalent saturated hydrocarbon cyclic group having 3 to 10 carbon atoms, and examples thereof are a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group (or bicyclo[2.2.1]heptyl group), a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, and a bicyclo[2.2.2]octyl group. The term “C₃-C₁₀ cycloalkylene group” as used herein refers to a divalent group having a structure corresponding to the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group” as used herein refers to a monovalent cyclic group that further includes, in addition to a carbon atom, at least one heteroatom as a ring-forming atom and has 1 to 10 carbon atoms, and examples thereof are a 1,2,3,4-oxatriazolidinyl group, a tetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkylene group” as used herein refers to a divalent group having a structure corresponding to the C₁-C₁₀ heterocycloalkyl group.

The term C₃-C₁₀ cycloalkenyl group used herein refers to a monovalent cyclic group that has three to ten carbon atoms and at least one carbon-carbon double bond in the ring thereof and no aromaticity, and examples thereof are a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The term “C₃-C₁₀ cycloalkenylene group” as used herein refers to a divalent group having a structure corresponding to the C₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group” as used herein refers to a monovalent cyclic group that has, in addition to a carbon atom, at least one heteroatom as a ring-forming atom, 1 to 10 carbon atoms, and at least one double bond in the cyclic structure thereof. Examples of the C₁-C₁₀ heterocycloalkenyl group include a 4,5-dihydro-1,2,3,4-oxatriazolyl group, a 2,3-dihydrofuranyl group, and a 2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylene group” as used herein refers to a divalent group having a structure corresponding to the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system having six to sixty carbon atoms, and the term “C₆-C₆₀ arylene group” as used herein refers to a divalent group having a carbocyclic aromatic system having six to sixty carbon atoms. Examples of the C₆-C₆₀ aryl group are a phenyl group, a pentalenyl group, a naphthyl group, an azulenyl group, an indacenyl group, an acenaphthyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a heptalenyl group, a naphthacenyl group, a picenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, and an ovalenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀ arylene group each include two or more rings, the rings may be fused with each other.

The term “C₁-C₆₀ heteroaryl group” as used herein refers to a monovalent group having a heterocyclic aromatic system that has, in addition to a carbon atom, at least one heteroatom as a ring-forming atom, and 1 to 60 carbon atoms. The term “C₁-C₆₀ heteroarylene group” as used herein refers to a divalent group having a heterocyclic aromatic system that has, in addition to a carbon atom, at least one heteroatom as a ring-forming atom, and 1 to 60 carbon atoms. Examples of the C₁-C₆₀ heteroaryl group are a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, a benzoquinolinyl group, an isoquinolinyl group, a benzoisoquinolinyl group, a quinoxalinyl group, a benzoquinoxalinyl group, a quinazolinyl group, a benzoquinazolinyl group, a cinnolinyl group, a phenanthrolinyl group, a phthalazinyl group, and a naphthyridinyl group. When the C₁-C₆₀ heteroaryl group and the C₁-C₆₀ heteroarylene group each include two or more rings, the rings may be fused with each other.

The term “monovalent non-aromatic fused polycyclic group” as used herein refers to a monovalent group (for example, having 8 to 60 carbon atoms) having two or more rings fused to each other, only carbon atoms as ring-forming atoms, and no aromaticity in its entire molecular structure. Examples of the monovalent non-aromatic fused polycyclic group are an indenyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, an indenophenanthrenyl group, and an indeno anthracenyl group. The term “divalent non-aromatic fused polycyclic group” as used herein refers to a divalent group having a structure corresponding to a monovalent non-aromatic fused polycyclic group.

The term “monovalent non-aromatic fused heteropolycyclic group” as used herein refers to a monovalent group (for example, having 1 to 60 carbon atoms) having two or more rings fused to each other, at least one heteroatom other than carbon atoms, as a ring-forming atom, and non-aromaticity in its entire molecular structure. Examples of the monovalent non-aromatic fused heteropolycyclic group are a pyrrolyl group, a thiophenyl group, a furanyl group, an indolyl group, a benzoindolyl group, a naphtho indolyl group, an isoindolyl group, a benzoisoindolyl group, a naphthoisoindolyl group, a benzosilolyl group, a benzothiophenyl group, a benzofuranyl group, a carbazolyl group, a dibenzosilolyl group, a dibenzothiophenyl group, a dibenzofuranyl group, an azacarbazolyl group, an azafluorenyl group, an azadibenzosilolyl group, an azadibenzothiophenyl group, an azadibenzofuranyl group, a pyrazolyl group, an imidazolyl group, a triazolyl group, a tetrazolyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, an isothiazolyl group, an oxadiazolyl group, a thiadiazolyl group, a benzopyrazolyl group, a benzimidazolyl group, a benzoxazolyl group, a benzothiazolyl group, a benzoxadiazolyl group, a benzothiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an imidazotriazinyl group, an imidazopyrazinyl group, an imidazopyridazinyl group, an indenocarbazolyl group, an indolocarbazolyl group, a benzofurocarbazolyl group, a benzothienocarbazolyl group, a benzosilolocarbazolyl group, a benzoindolocarbazolyl group, a benzocarbazolyl group, a benzonaphthofuranyl group, a benzonaphthothiophenyl group, a benzonaphthosilolyl group, a benzofurodibenzofuranyl group, a benzofurodibenzothiophenyl group, and a benzothienodibenzothiophenyl group. The term “divalent non-aromatic heterofused polycyclic group” as used herein refers to a divalent group having a structure corresponding to a monovalent non-aromatic heterofused polycyclic group.

The term “C₆-C₆₀ aryloxy group” as used herein indicates —OA₁₀₂ (wherein A₁₀₂ is the C₆-C₆₀ aryl group), and the term “C₆-C₆₀ arylthio group” as used herein indicates —SA₁₀₃ (wherein A₁₀₃ is the C₆-C₆₀ aryl group).

Q₁ to Q₃ used herein may each independently be: hydrogen; deuterium; —F; —Cl; —Br; —I; a hydroxyl group; a cyano group; a nitro group; C₁-C₆₀ alkyl group; C₂-C₆₀ alkenyl group; C₂-C₆₀ alkynyl group; C₁-C₆₀ alkoxy group; or a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group, each unsubstituted or substituted with deuterium, —F, a cyano group, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a biphenyl group, or any combination thereof.

The term “R_(10a)” as used herein refers to:

deuterium (-D), —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, or a nitro group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, or a C₁-C₆₀ alkoxy group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁), —S(═O)₂(Q₁₁), —P(═O)(Q₁₁)(Q₁₂), or any combination thereof, a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, or a C₆-C₆₀ arylthio group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₆₀ carbocyclic group, a C₁-C₆₀ heterocyclic group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂),—B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), —P(═O)(Q₂₁)(Q₂₂), or any combination thereof, or

—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), or —P(═O)(Q₃₁)(Q₃₂),

Q₁₁ to Q₁₃, Q₂₁ to Q₂₃ and Q₃₁ to Q₃₃ used herein may each independently be: hydrogen; deuterium; —F; —Cl; —Br; —I; a hydroxyl group; a cyano group; a nitro group; C₁-C₆₀ alkyl group; C₂-C₆₀ alkenyl group; C₂-C₆₀ alkynyl group; C₁-C₆₀ alkoxy group; or a C₃-C₆₀ carbocyclic group or a C₁-C₆₀ heterocyclic group, each unsubstituted or substituted with deuterium, —F, a cyano group, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a biphenyl group, or any combination thereof.

The term “heteroatom” as used herein refers to any atom other than a carbon atom. Examples of the heteroatom are O, S, N, P, Si, B, Ge, Se, and any combination thereof.

As used herein, the term “Ph” refers to a phenyl group, the term “Me” refers to a methyl group, the term “Et” refers to an ethyl group, the term “ter-Bu” or “But” refers to a tert-butyl group, and the term “OMe” refers to a methoxy group.

The term “biphenyl group” as used herein refers to “a phenyl group substituted with a phenyl group.” In other words, the “biphenyl group” is a substituted phenyl group having a C₆-C₆₀ aryl group as a substituent.

The term “terphenyl group” as used herein refers to “a phenyl group substituted with a biphenyl group”. In other words, the “terphenyl group” is a substituted phenyl group having, as a substituent, a C₆-C₆₀ aryl group substituted with a C₆-C₆₀ aryl group.

* and *′ as used herein, unless defined otherwise, each refer to a binding site to a neighboring atom in a corresponding formula.

EXAMPLES Preparation Example 1: Ink A

The compound ZnO (diameter: 4 nm) (3.5 wt %) as inorganic nanoparticles, and 2 mL of a mixed solvent in which propylene glycol methyl ether acetate and triethylene glycol monomethyl ether were mixed at a volume ratio of 5:5 as a solvent, were used to prepare nanoparticle ink composition.

Preparation Example 2: Ink B

A nanoparticle ink composition was prepared in the same manner as in Preparation Example 1, except that 2 mL of diethylene glycol monobutyl ether was used as a solvent.

Comparative Preparation Example 1: Ink C

A nanoparticle ink composition was prepared in the same manner as in Preparation Example 1, except that 2 mL of triethylene glycol monobutyl ether was used as a solvent.

Comparative Preparation Example 2: Ink D

A nanoparticle ink composition was prepared in the same manner as in Preparation Example 1, except that 2 mL of triethylene glycol monomethyl ether was used as a solvent and ZnO nanoparticles having a diameter of 5.5 nm were used.

Comparative Preparation Example 3: Ink E

The following 2-methoxy ethanol, water, and WO₃ nanoparticles having a diameter of 5.5 nm were mixed at a weight ratio of 90:6:4 to prepare 2 mL of a nanoparticle ink composition.

Comparative Preparation Example 4: Ink F

The following 2-methoxy ethanol, water, and WO₃ nanoparticles having a diameter of 5.5 nm were mixed at a weight ratio of 95:3:2 to prepare 2 mL of a nanoparticle ink composition.

Comparative Preparation Example 5: Ink G

The following 1,3-propane diol, diethylene glycol ether acetate, and ZnO nanoparticles having a diameter of 5.5 nm were mixed at a weight ratio of 63:34:3 to prepare 2 mL of a nanoparticle ink composition.

Preparation Example 3: Ink H

A nanoparticle ink composition was prepared in the same manner as in Preparation Example 1, except that TiO₂ having a diameter of 4 nm was used as inorganic nanoparticles.

Evaluation Example: Jetting Characteristics

FIG. 4 is a photographic result showing jetting test results of an ink composition of Example 1 of an embodiment. FIG. 5 is a photographic result showing jetting test results of an ink composition of Example 2. FIG. 6 is a photographic result jetting test results of an ink composition of Comparative Example 1. FIG. 7 a photographic result jetting test results of an ink composition of Comparative Example 2.

The nanoparticle ink compositions prepared in Preparation Example 1 to Preparation Example 3 and Comparative Preparation Example 1 to Comparative Preparation Example 5 were applied to pixels partitioned on a liquid-repellent substrate by an inkjet printing method (nozzle diameter of an inkjet printer: 21 μm), the Ohnesorge number and jetting characteristics of each of the nanoparticle ink composition were evaluated, and results are shown in Table 1 and FIGS. 4 to 7. All compositions were jetted from the same inkjet printer under substantially the same conditions.

In the jetting characteristics evaluation item of Table 1, “O” indicates that the nanoparticle ink compositions were properly jetted, and “X” indicates that the nanoparticle ink compositions were improperly jetted.

TABLE 1 PE 1 PE 2 CPE 1 CPE 2 CPE 3 CPE 4 CPE 5 PE 3 Ohne-sorge 0.143 0.200 0.203 0.224 0.0571 0.0578 1.11 0.105 number Jetting O O X X X X X O PE: Preparation Example CPE: Comparative Preparation Example

Referring to Table 1, only the nanoparticle ink compositions of Preparation Example 1 to Preparation Example 3 that satisfies the Ohnesorge number range (0.1 to 0.2) according to the embodiments were properly injected, and in other cases in other inorganic nanoparticles are included or even when the same inorganic nanoparticles are included, the Ohnesorge number is outside the range described above, jetting may occur improperly.

In addition, referring to FIGS. 4 to 7, it is confirmed that the nanoparticle ink compositions of Preparation Examples 1 to 3, which are nanoparticle ink compositions of the embodiments, were jetted without clogging the ink head, whereas the ink compositions of Comparative Preparation Examples 1 to 5 were jetted improperly.

Because nanoparticle ink compositions have an appropriate range of the Ohnesorge number, the nanoparticle ink compositions including inorganic nanoparticles can be easily jetted, and light-emitting devices including inorganic nanoparticles can be easily manufactured by inkjet printing. Some of the advantages that may be achieved by illustrative implementations of the invention and/or illustrative methods of the invention include easily jetted inorganic nanoparticles and easily manufactured light-emitting devices by inkjet printing.

Although certain embodiments and implementations have been described herein, other embodiments and modifications will be apparent from this description. Accordingly, the inventive concepts are not limited to such embodiments, but rather to the broader scope of the appended claims and various obvious modifications and equivalent arrangements as would be apparent to a person of ordinary skill in the art. 

What is claimed is:
 1. A nanoparticle ink composition comprising: a solvent; and one or more inorganic nanoparticles substantially dispersed in the solvent, wherein the inorganic nanoparticles comprise one or more quantum dots or a metal oxide having a diameter of about 20 nm or less, and the nanoparticle ink composition has an Ohnesorge number of about 0.1 to about 0.2.
 2. The nanoparticle ink composition of claim 1, wherein a surface tension of the nanoparticle ink composition is from about 20 dyne/cm to about 50 dyne/cm.
 3. The nanoparticle ink composition of claim 1, wherein a viscosity of the nanoparticle ink composition at a temperature of 25° C. is from about 1 cP to about 12 cP.
 4. The nanoparticle ink composition of claim 1, wherein a density of the nanoparticle ink composition is from about 0.8 g/cm³ to about 2.0 g/cm³.
 5. The nanoparticle ink composition of claim 1, wherein the solvent comprises an alcohol-based solvent having two or more carbon atoms, an ether-based solvent, an aromatic solvent, or a combination thereof.
 6. The nanoparticle ink composition of claim 1, wherein an amount of the inorganic nanoparticles is about 10 wt % or less based on a total weight of the nanoparticle ink composition.
 7. The nanoparticle ink composition of claim 1, wherein the one or more quantum dots comprise a semiconductor compound of Groups II-VI, a semiconductor compound of Groups III-V, a semiconductor compound of Groups III-VI, a semiconductor compound of Groups I, III, and VI, a semiconductor compound of Groups IV-VI, a semiconductor compound of an element or a compound Group IV, or any combination thereof.
 8. The nanoparticle ink composition of claim 1, wherein the one or more quantum dots comprise InP, GaP, InGaP, ZnSe, ZnS, ZnSeTe, or any combination thereof.
 9. The nanoparticle ink composition of claim 1, wherein the metal oxide comprises an alkali metal oxide, an alkaline earth metal-containing oxide, a rare earth metal-containing oxide, a transition metal oxide, or a combination thereof.
 10. The nanoparticle ink composition of claim 1, wherein the metal oxide comprises an oxide of beryllium, magnesium, calcium, strontium, barium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, iron, zinc, aluminum, gallium, indium, silicon, germanium, tin, copper, or any combination thereof.
 11. The nanoparticle ink composition of claim 1, wherein the metal oxide comprises ZnO, TiO₂, WO₃, MoO₃, or a combination thereof.
 12. A light-emitting device comprising: a first electrode; a second electrode facing the first electrode; and an interlayer between the first electrode and the second electrode, wherein the interlayer comprises an emission layer, and at least one of layers included in the interlayer is made from the nanoparticle ink composition of claim
 1. 13. The light-emitting device of claim 12, wherein the emission layer is made from using the nanoparticle ink composition.
 14. The light-emitting device of claim 13, wherein the nanoparticle ink composition includes quantum dots.
 15. The light-emitting device of claim 12, wherein the interlayer further comprises a hole-transporting region between the first electrode and the emission layer, and an electron-transporting region between the emission layer and the second electrode.
 16. The light-emitting device of claim 15, wherein the hole-transporting region includes a hole injection layer, a hole-transporting layer, an emission auxiliary layer, an electron-blocking layer, or a combination thereof, the electron-transporting region includes a buffer layer, a hole-blocking layer, an electron control layer, an electron-transporting layer, an electron injection layer, or a combination thereof, and at least one of layers included in the hole-transporting region and the electron-transporting region is made from the nanoparticle ink composition.
 17. The light-emitting device of claim 16, wherein the nanoparticle ink composition includes the metal oxide.
 18. A method of manufacturing a light-emitting device, the light-emitting device comprising: a first electrode; a second electrode facing the first electrode; and an interlayer between the first electrode and the second electrode, wherein the interlayer includes an emission layer, a hole-transporting region between the first electrode and the emission layer, and an electron-transporting region between the emission layer and the second electrode; and the method comprising the steps of: (A) forming the hole-transporting region on the first electrode, (B) forming the emission layer on the hole-transporting region, and (C) forming the electron-transporting region on the emission layer, wherein at least one of the steps (A) to (C) includes using a solution comprising the nanoparticle ink composition of claim
 1. 19. The method of claim 18, wherein the solution is used in an inkjet printing method.
 20. The method of claim 19, wherein the inkjet printing method comprises jetting the nanoparticle ink composition from an inkjet printer nozzle with a diameter of about 25 μm or less. 